Cryptanalysis of a key exchange scheme based on block matrices Articles uri icon

publication date

  • August 2014


  • 276

International Standard Serial Number (ISSN)

  • 0020-0255

Electronic International Standard Serial Number (EISSN)

  • 1872-6291


  • In this paper we describe a cryptanalysis of a key exchange scheme recently proposed by Alvarez, Tortosa, Vicent and Zamora. The scheme is based on exponentiation of block matrices over a finite field of prime order, and its security is claimed to rely in the hardness of a discrete logarithm problem in a subgroup of GL(n)(Z(p)). However, the proposal's design allows for a clean attack strategy which exploits the fact that exponents are at some point added instead of multiplied as in a standard Diffie-Hellman construction. This strategy is moreover successful for a much more general choice of parameters than that put forward by Alvarez et al.


  • Mathematics


  • block matrix; cryptanalysis; discrete logarithm problem; finite field; key exchange scheme